'''
if elif else
not and or 逻辑非,逻辑与,逻辑或
'''

a = True

if a:
    print("true")
else:
    print("false")

a = 16

if a < 6:
    print("小孩")
if a>=6 and a < 18:
    print("未成年")
if a >= 18:
    print("成年")


b = False
if not b:
    print("true")